CVE-2023-46836
Vulnerability from cvelistv5
Published
2024-01-05 16:34
Modified
2024-08-02 20:53
Severity ?
Summary
The fixes for XSA-422 (Branch Type Confusion) and XSA-434 (Speculative Return Stack Overflow) are not IRQ-safe. It was believed that the mitigations always operated in contexts with IRQs disabled. However, the original XSA-254 fix for Meltdown (XPTI) deliberately left interrupts enabled on two entry paths; one unconditionally, and one conditionally on whether XPTI was active. As BTC/SRSO and Meltdown affect different CPU vendors, the mitigations are not active together by default. Therefore, there is a race condition whereby a malicious PV guest can bypass BTC/SRSO protections and launch a BTC/SRSO attack against Xen.
References
security@xen.orghttps://xenbits.xenproject.org/xsa/advisory-446.htmlPatch, Vendor Advisory
af854a3a-2127-422b-91ae-364da2661108https://xenbits.xenproject.org/xsa/advisory-446.htmlPatch, Vendor Advisory
Impacted products
Vendor Product Version
Show details on NVD website

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        ],
        "title": "CVE Program Container"
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    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "product": "Xen",
          "vendor": "Xen",
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        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "This issue was discovered by Andrew Cooper of XenServer.\n"
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      "datePublic": "2023-11-14T12:00:00Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "The fixes for XSA-422 (Branch Type Confusion) and XSA-434 (Speculative\nReturn Stack Overflow) are not IRQ-safe.  It was believed that the\nmitigations always operated in contexts with IRQs disabled.\n\nHowever, the original XSA-254 fix for Meltdown (XPTI) deliberately left\ninterrupts enabled on two entry paths; one unconditionally, and one\nconditionally on whether XPTI was active.\n\nAs BTC/SRSO and Meltdown affect different CPU vendors, the mitigations\nare not active together by default.  Therefore, there is a race\ncondition whereby a malicious PV guest can bypass BTC/SRSO protections\nand launch a BTC/SRSO attack against Xen.\n"
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      "title": "x86: BTC/SRSO fixes not fully effective",
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          "value": "Running only HVM or PVH VMs will avoid the vulnerability.\n"
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    "dateReserved": "2023-10-27T07:55:35.332Z",
    "dateUpdated": "2024-08-02T20:53:21.940Z",
    "state": "PUBLISHED"
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  }
}


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